There were a lot of older treadle machines repainted (often the "crinkle" finish) and electrified when raw materials were scares during the wars. BTW - I beleive Singer only officially used black crinkle, so most likely the brown is a refurbished machine.
However, if it takes a drop in bobbin, you've misidentified the number, as the Model 66 was not made until after 1900. It should have a letter or two in front of the number.
A picture would be great to help identify the model exactly.